Clinical heart transplantation using human cadaver organs remains the most effective therapy for end-stage heart disease; however, the severe shortage of organs has led to alternative strategies utilizing non-human organs (xenografts). In human allotransplantation, the predominant antigenic differences between donor and recipient are confined to the major histocompatibility and blood group antigens. In contrast, a xenograft is able to express a variety of antigens, in addition to the major histocompatibility and blood group antigens, which are not expressed by human cells and can elicit anti-xenograft immunity in human recipients.

Keywords: discordant xenotransplantation, anti-Galantibodies, delayed rejection, T lymphocytes, transgenic animals